大口径90°弯管内三维水力特性数值模拟研究  

Research on three-dimensional numerical simulation of flow hydraulic characteristics in large-diameter 90°vertical bend

作　　者：夏鹏飞[1] 马强[1] 马琳[1] 乔丹[1] 姚锦华 武易 XIA Peng-fei;MA Qiang;MA Lin;QIAO Dan;YAO Jin-hua;WU Yi(Yangling Vocational and Technical College, Xianyang 712100, China)

机构地区：[1]杨凌职业技术学院,咸阳712100

出　　处：《水道港口》2020年第5期550-557,共8页Journal of Waterway and Harbor

基　　金：杨凌职业技术学院2019年自然科学基金项目(A2019004)。

摘　　要：采用fluent软件,选择标准k-ε紊流模型对大口径90°竖直弯管内的流动进行了三维数值模拟。在上游水箱断面自编程序使用了水位边界条件,对4种恒压水头下的上游竖管、弯管、下游水平管内的速度场和压力场进行计算,得到各水头下弯管内二次流动现象(迪恩涡)。对比相同水头下网格疏密性对二次流计算的差异,分析了弯管管道内的压力场、速度场的分布规律和各水头下弯管不同角度内外壁面的空化数。结果表明:疏密网格均能模拟出迪恩涡,但计算精度偏差值较大;各工况下空化数最低值均在10°截面上的内壁面出现,但均大于工程要求的0.3;各工况下,弯管内压强和速度变化规律相似,弯管段内壁压强均低于外壁压强,该压差维持着弯管内的二次流动。Three dimensional numerical simulation of water gas two-phase flow in large-diameter 90°vertical bend was carried using FLUENT software,the standard turbulence model and VOF method.Especially when the water level boundary conditions at inlet section are used by self writing programs.The velocity field and pressure field in the upstream vertical pipe,bend and downstream horizontal pipe under four kinds of water heads,the secondary flow phenomenon(Dean Vortex)in the bend under each water head,and the calculation difference of mesh density to the secondary flow under the same water head were obtained.The simulation results showed that the dense mesh could simulate Dean Vortex,but the calculation accuracy deviation was large;the lowest value of cavitation number in each working condition appeared on the inner wall surface of 10°section,but it was greater than 0.3 required by the project;under different working conditions the pressure and velocity in the elbow were similar,and the pressure on the inner wall of the elbow was lower than that on the outer wall which maintained the secondary flow in the elbow.

关 键 词：90°弯管 数值模拟 水气二相流 二次流动 

分 类 号：U65[交通运输工程—港口、海岸及近海工程]